1. Field of the Invention
The present invention pertains to a pressure plate assembly for a friction clutch comprising a housing arrangement; a pressure plate which is inside the housing arrangement and which can rotate with it around an axis of rotation; a force-exerting arrangement, preferably a force-storing device, which can be supported against the housing arrangement and the pressure plate; and a wear take-up device in the path of force transmission between the force-exerting arrangement and the pressure plate, comprising at least one wear take-up element which can be moved to compensate for wear.
2. Description of the Related Art
In pressure plate assemblies in which the wear take-up device acts automatically to compensate for wear, the minimum of one wear take-up element is pretensioned by some type of pretensioning device, usually a pretensioning spring, which tries to push the element in a certain direction. After a blocking action has been released, the wear take-up element is free to move in this direction, and under certain conditions it can then compensate for the wear which has occurred. To ensure that the pretension on the wear take-up element can cause the element to carry out its wear take-up function only under certain conditions, measures must be taken to prevent the minimum of one wear take-up element from shifting its position relative to the pressure plate during those phases in which no wear take-up is supposed to occur. For this purpose it is known, for example, that leaf spring elements can be used, which can serve to detect the wear or the occurrence of wear, but which also have the function of ensuring through their elastic pretension that the wear take-up element does not shift position before any wear has occurred or after compensation has been made for previous wear. The opposing force provided by an element of this type, such as a leaf spring element, must be sufficiently strong to oppose the pretensioning force acting on the minimum of one take-up element even when, for example, vibrations occur in the system. Especially when this type of element is simultaneously fulfilling the function of a wear detection element, however, providing it with a sufficient degree of stiffness can impair the wear-detecting behavior and possibly even the overall behavior of the clutch.